Improve building ignore file lists

The routines to push and pop ignore files while traversing a
directory had some issues. In particular, setting up the initial
list would sometimes push an ignore file before it ought to be
applied if the starting path was a directory containing an ignore
file. Also, the pop function was not always matching the right
part of the path and would fail to pop ignores from the list in
some cases.

This adds some tests that exercise a particular problematic case
and then fixes the problems that I could find related to this.

At some point, I'd like to isolate this ignore rule management
code and rewrite it, but that's a larger project and right now,
I'll opt to just try to fix the broken behaviors.

src/ignore.c

@@ -159,17 +159,26 @@ int git_ignore__push_dir(git_ignores *ign, const char *dir)
 {
 	if (git_buf_joinpath(&ign->dir, ign->dir.ptr, dir) < 0)
 		return -1;
-	else
-		return push_ignore_file(
-			ign->repo, ign, &ign->ign_path, ign->dir.ptr, GIT_IGNORE_FILE);
+
+	return push_ignore_file(
+		ign->repo, ign, &ign->ign_path, ign->dir.ptr, GIT_IGNORE_FILE);
 }
 
 int git_ignore__pop_dir(git_ignores *ign)
 {
 	if (ign->ign_path.length > 0) {
 		git_attr_file *file = git_vector_last(&ign->ign_path);
-		if (git__suffixcmp(ign->dir.ptr, file->key + 2) == 0)
+		size_t keylen = strlen(file->key);
+
+		while (keylen && file->key[keylen] != '/')
+			keylen--;
+		keylen -= 1; /* because we will skip "0#" prefix */
+
+		if (ign->dir.size > keylen &&
+			!memcmp(ign->dir.ptr + ign->dir.size - keylen,
+					file->key + 2, keylen))
 			git_vector_pop(&ign->ign_path);
+
 		git_buf_rtruncate_at_char(&ign->dir, '/');
 	}
 	return 0;
@@ -298,12 +307,9 @@ int git_ignore_path_is_ignored(
 		path.full.size = (tail - path.full.ptr);
 		path.is_dir = (tail == end) ? full_is_dir : true;
 
-		/* update ignores for new path fragment */
-		if (path.basename == path.path)
-			error = git_ignore__for_path(repo, path.path, &ignores);
-		else
-			error = git_ignore__push_dir(&ignores, path.basename);
-		if (error < 0)
+		/* initialize ignores the first time through */
+		if (path.basename == path.path &&
+			(error = git_ignore__for_path(repo, path.path, &ignores)) < 0)
 			break;
 
 		/* first process builtins - success means path was found */
@@ -327,6 +333,10 @@ int git_ignore_path_is_ignored(
 		if (tail == end)
 			break;
 
+		/* now add this directory to list of ignores */
+		if ((error = git_ignore__push_dir(&ignores, path.path)) < 0)
+			break;
+
 		/* reinstate divider in path */
 		*tail = '/';
 		while (*tail == '/') tail++;

src/ignore.h

@@ -24,14 +24,15 @@
  */
 typedef struct {
 	git_repository *repo;
-	git_buf dir;
+	git_buf dir; /* current directory reflected in ign_path */
 	git_attr_file *ign_internal;
 	git_vector ign_path;
 	git_vector ign_global;
 	int ignore_case;
 } git_ignores;
 
-extern int git_ignore__for_path(git_repository *repo, const char *path, git_ignores *ign);
+extern int git_ignore__for_path(
+	git_repository *repo, const char *path, git_ignores *ign);
 
 extern int git_ignore__push_dir(git_ignores *ign, const char *dir);
 

src/iterator.c

@@ -1350,7 +1350,7 @@ int git_iterator_for_workdir_ext(
 	wi->fi.update_entry_cb = workdir_iterator__update_entry;
 
 	if ((error = iterator__update_ignore_case((git_iterator *)wi, flags)) < 0 ||
-		(error = git_ignore__for_path(repo, "", &wi->ignores)) < 0)
+		(error = git_ignore__for_path(repo, ".gitignore", &wi->ignores)) < 0)
 	{
 		git_iterator_free((git_iterator *)wi);
 		return error;

src/path.c

@@ -603,7 +603,7 @@ int git_path_find_dir(git_buf *dir, const char *path, const char *base)
 	}
 
 	/* call dirname if this is not a directory */
-	if (!error && git_path_isdir(dir->ptr) == false)
+	if (!error) /* && git_path_isdir(dir->ptr) == false) */
 		error = git_path_dirname_r(dir, dir->ptr);
 
 	if (!error)

tests-clar/status/ignore.c

@@ -493,3 +493,90 @@ void test_status_ignore__filenames_with_special_prefixes_do_not_interfere_with_s
 		git_buf_free(&file);
 	}
 }
+
+void test_status_ignore__issue_1766_negated_ignores(void)
+{
+	int ignored = 0;
+	unsigned int status;
+
+	g_repo = cl_git_sandbox_init("empty_standard_repo");
+
+	cl_git_pass(git_futils_mkdir_r(
+		"empty_standard_repo/a", NULL, 0775));
+	cl_git_mkfile(
+		"empty_standard_repo/a/.gitignore", "*\n!.gitignore\n");
+	cl_git_mkfile(
+		"empty_standard_repo/a/ignoreme", "I should be ignored\n");
+
+	cl_git_pass(git_status_should_ignore(&ignored, g_repo, "a/.gitignore"));
+	cl_assert(!ignored);
+
+	cl_git_pass(git_status_should_ignore(&ignored, g_repo, "a/ignoreme"));
+	cl_assert(ignored);
+
+	cl_git_pass(git_futils_mkdir_r(
+		"empty_standard_repo/b", NULL, 0775));
+	cl_git_mkfile(
+		"empty_standard_repo/b/.gitignore", "*\n!.gitignore\n");
+	cl_git_mkfile(
+		"empty_standard_repo/b/ignoreme", "I should be ignored\n");
+
+	cl_git_pass(git_status_should_ignore(&ignored, g_repo, "b/.gitignore"));
+	cl_assert(!ignored);
+
+	cl_git_pass(git_status_should_ignore(&ignored, g_repo, "b/ignoreme"));
+	cl_assert(ignored);
+
+	/* shouldn't have changed results from first couple either */
+
+	cl_git_pass(git_status_should_ignore(&ignored, g_repo, "a/.gitignore"));
+	cl_assert(!ignored);
+	cl_git_pass(git_status_should_ignore(&ignored, g_repo, "a/ignoreme"));
+	cl_assert(ignored);
+
+	/* status should find the two ignore files and nothing else */
+
+	cl_git_pass(git_status_file(&status, g_repo, "a/.gitignore"));
+	cl_assert_equal_i(GIT_STATUS_WT_NEW, (int)status);
+
+	cl_git_pass(git_status_file(&status, g_repo, "a/ignoreme"));
+	cl_assert_equal_i(GIT_STATUS_IGNORED, (int)status);
+
+	cl_git_pass(git_status_file(&status, g_repo, "b/.gitignore"));
+	cl_assert_equal_i(GIT_STATUS_WT_NEW, (int)status);
+
+	cl_git_pass(git_status_file(&status, g_repo, "b/ignoreme"));
+	cl_assert_equal_i(GIT_STATUS_IGNORED, (int)status);
+
+	{
+		git_status_options opts = GIT_STATUS_OPTIONS_INIT;
+		status_entry_counts counts;
+		static const char *paths[] = {
+			"a/.gitignore",
+			"a/ignoreme",
+			"b/.gitignore",
+			"b/ignoreme",
+		};
+		static const unsigned int statuses[] = {
+			GIT_STATUS_WT_NEW,
+			GIT_STATUS_IGNORED,
+			GIT_STATUS_WT_NEW,
+			GIT_STATUS_IGNORED,
+		};
+
+		memset(&counts, 0x0, sizeof(status_entry_counts));
+		counts.expected_entry_count = 4;
+		counts.expected_paths = paths;
+		counts.expected_statuses = statuses;
+
+		opts.flags = GIT_STATUS_OPT_DEFAULTS;
+
+		cl_git_pass(git_status_foreach_ext(
+			g_repo, &opts, cb_status__normal, &counts));
+
+		cl_assert_equal_i(counts.expected_entry_count, counts.entry_count);
+		cl_assert_equal_i(0, counts.wrong_status_flags_count);
+		cl_assert_equal_i(0, counts.wrong_sorted_path);
+	}
+}
+